PNIVEBSITY  OF   CALIFORHIA   PPBLICATIOK8 

COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,  CALIFORNIA 


SWEET  SORGHUMS  FOR  FORAGE 


BY 

B.  A.  MADSON 


BULLETIN  No.  293 

April,  1918 


UNIVERSITY  OF  CALIFORNIA  PRESS 

BERKELEY 

1918 


Benjamin  Ide  Wheelee,  President  of  the  University. 

EXPERIMENT  STATION  STAFF 

HEADS  OP  DIVISIONS 

Thomas  Forsyth  Hunt,  Director. 
Edward  J.  Wickson,  Horticulture  (Emeritus). 

Herbert  J.  Webber,  Director  Citrus  Experiment  Station;  Plant  Breeding. 
Hubert  E.  Van  Norman,  Vice-Director;  Dairy  Management. 
William  A.  Setchell,  Botany. 
Myer  E.  Jaffa,  Nutrition. 
Charles  W.  Woodworth,  Entomology. 
Ralph  E.  Smith,  Plant  Pathology. 
J.  Eliot  Coit,  Citriculture. 
John  W.  Gilmore,  Agronomy. 
Charles  F.  Shaw,  Soil  Technology. 
John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 
Frederic  T.  Bioletti,  Viticulture  and  Enology. 
Warren  T.  Clarke,  Agricultural  Extension. 
John  S.  Burd,  Agricultural  Chemistry. 
Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 
Clarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 
Ernest  B.  Babcock,  Genetics. 
Gordon  H.  True,  Animal  Husbandry. 
James  T.  Barrett,  Plant  Pathology. 
Fritz  W.  Woll,  Animal  Nutrition. 
Walter  Mulpord,  Forestry. 
W.  P.  Kelley,  Agricultural  Chemistry. 
H.  J.  Quayle,  Entomology. 
J.  B.  Davidson,  Agricultural  Engineering. 
Elwood  Mead,  Rural  Institutions. 
H.  S.  Reed,  Plant  Physiology. 
W.  L.  Howard,  Pomology. 
fFRANK  Adams,  Irrigation  Investigations. 
C.  L.  Roadhouse,  Dairy  Industry. 
O.  J.  Kern,  Agricultural  Education. 
John  E.  Dougherty,  Poultry  Husbandry. 
S.  S.  Rogers,  Olericulture. 
R.  S.  Vaile,  Orchard  Management. 
J.  G.  Moodey,  Assistant  to  the  Director. 
Mrs.  D.  L.  Bunnell,  Librarian. 


t  In  co-operation  with  office  of  Public  Roads  and  Rural   Engineering,   U.    S. 
Department  of  Agriculture. 


SWEET  SORGHUMS  FOR  FORAGE 

By  B.  A.  MADSON 


At  no  time  in  the  history  of  California  has  the  demand  for  forage 
crops  been  as  great  as  now.  The  California  farmer  realizes  that  if  he 
is  to  contribute  materially  to  the  much  needed  supply  of  meat,  he 
will  have  to  depend  more  upon  forage  crops  and  less  on  natural  range 
in  order  to  finish  his  animals  for  market  as  quickly  as  possible.  The 
dairy  farmer  too  is  cognizant  of  the  fact  that  forage  and  especially 
silage  is  essential  to  the  success  of  the  dairy  industry.  For  these 
purposes  crops  are  required  which  can  be  depended  upon  to  produce 
relatively  large  amounts  of  feed  during  the  summer  months.  The 
crops  which  thus  far  have  shown  the  greatest  promise  in  filling  this 
need  are  the  sweet  or  saccharine  sorghums.  Their  special  value  lies, 
not  only  in  their  drouth  resistance,  and  adaptation  to  California  con- 
ditions, but  also  in  the  fact  that  they  fit  well  into  the  cropping  scheme 
on  the  general  livestock  farm,  and  may  be  used  in  the  ration  in  a 
number  of  ways.  One  of  the  important  uses  to  which  sorghums  may 
be  put  is  as  stock  feed  in  the  form  of  silage.  For  this  purpose  Woll 
and  Voorhies  have  shown  that  on  the  basis  of  dry  matter,  sorghum 
silage  compares  favorably  with  Indian  corn  in  feed  value.1  Sor- 
ghums may  also  be  used  as  fodder  and  because  of  their  leafy  character 
and  succulence,  yield  a  palatable  and  nutritious  roughage.  Under 
certain  conditions,  the  sorghum  may  also  be  used  for  hay  or  pasture. 
For  this  purpose,  however,  sudan  grass,  because  of  its  greater  per- 
sistence and  finer  leaves  and  stems,  is  usually  to  be  preferred. 

ADAPTATION 

Like  other  members  of  the  sorghum  family,  the  sweet  sorghums 
prefer  a  rather  dry,  semi-arid  climate,  with  high  temperatures  during 
the  growing  season.  They  will,  however,  tolerate  lower  temperatures 
and  a  greater  degree  of  humidity  than  either  the  grain  sorghums  or 
sudan  grass.  In  general,  it  may  be  said  that  any  climate  that  is 
suitable  for  Indian  corn  is  also  suitable  for  the  sweet  sorghums.  In 
addition,  the  sorghums  have  the  advantage  of  being  much  more 
tolerant  of  drouth  than  Indian  corn. 


i  Univ.  Calif.  Agr.  Exp.  Sta.  Bui.  282. 


272  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Their  ability  to  withstand  drouth  is  apparently  due  to  their 
faculty  of  making  economical  use  of  the  water  supply  as  well  as  the 
ability  to  remain  partially  dormant  for  prolonged  periods  without 
injury.  The  root  system  of  the  sorghum  is  well  developed,  enabling 
the  plant  to  utilize  a  larger  portion  of  the  soil  moisture  than  most 
other  plants.  It  is  this  ability  to  make  the  fullest  use  of  the  moisture 
and  to  regulate  its  growth  in  accordance  with  the  supply  of  moisture, 
that  makes  the  crop  of  special  value  in  this  state. 

The  soil  requirements  of  the  sweet  sorghums  are  practically  the 
same  as  those  for  Indian  corn.  Free  working,  sandy  loam  soils  of 
good  water-holding  capacity  are  preferred  to  heavier  soils,  because 
of  their  high  fertility,  better  aeration,  and  the  greater  ease  with  which 
they  can  be  handled.  Soils  of  this  character  are  usually  warmer, 
facilitating  prompt  germination  and  rapid  root  development.  Other 
types  of  soil  may  be  used,  however,  provided  due  precaution  is 
taken  with  regard  to  the  time  of  planting  and  the  preparation  of 
the  seed  bed. 

In  general  the  sweet  sorghums  can  be  grown  in  practically  all 
agricultural  sections  of  California,  with  the  exception  of  those  directly 
exposed  to  the  cold  ocean  winds.  The  larger  valleys,  with  their  high 
temperatures,  and  deep,  fertile,  well  drained  soil,  are  particularly 
suited  to  this  crop.  As  a  source  of  fodder  and  silage,  they  are  the 
most  promising  of  any  crop  at  the  farmer's  command. 

VARIETIES 

The  sweet  sorghums  are  closely  related  to  the  grain  sorghums  and 
broom  corn,  as  well  as  to  sudan,  and  tunis  grass.  They  are  particu- 
larly characterized  by  the  fact  that  the  sap  contains  a  higher 
percentage  of  sugar,  which  renders  them  of  considerable  value  for 
syrup  making.  The  sugar  content  as  well  as  the  juiciness  of  the 
stem  varies  with  the  variety;  so  much  so,  in  fact,  that  the  line  of 
demarcation  between  the  sweet  sorghums  and  the  kafirs  can  not  be 
clearly  drawn.  As  a  class,  however,  the  sweet  sorghums  are  much 
more  succulent  and  leafy  than  the  grain  sorghums,  while  their  seeds 
are  small  and  hard  and  only  of  little  value  for  feed.  The  sweet 
sorghums  as  a  class  stool  or  tiller  more  abundantly  than  the  grain 
types. 

Of  the  large  number  of  varieties  introduced  into  or  developed  in 
this  country,  only  a  few  have  attained  wide  agricultural  importance. 
Only  the  more  prominent  of  these  or  the  ones  which  have  been  grown 
in  this  state  will  be  discussed  in  this  publication. 


SWEET  SORGHUMS  FOR  FORAGE 


273 


The  oldest,  as  well  as  the  most  widely  grown  variety  in  this 
country  is  the  Early  Amber.  Its  earliness  permits  its  growth  in 
regions  where  the  growing  season  is  too  short  for  other  varieties. 
Early  Amber  is  characterized  by  rather  slender  stalks,  varying  in 
height  from  six  to  ten  feet,  and  loose  open  heads  or  panicles  with 
black  glumes  enclosing  the  seeds.  Selections  of  the  Early  Amber 
known  as  Dakota  Amber  and  Minnesota  Amber  are  also  being  grown 
to  some  extent,  but  in  their  general  character  and  adaptation  they 
differ  but  little  from  the  parent  type. 


Fig.  1. — Honey  sorghum  under  irrigation  at  the  University  Farm,  Davis. 
This  variety  gives  good  yields  of  excellent  forage.  Note  the  dense  growth  of 
slender  leafy  stalks. 


Red  Amber  sorghum  is  similar  to  the  Early  Amber,  except  that 
it  makes  a  little  larger  growth,  is  a  little  later  maturing  and  has 
red  glumes  or  chaff  instead  of  black.  At  present  it  is  grown  only  to 
a  limited  extent,  though  it  possesses  distinct  advantage  over  this 
former  variety  as  a  forage  crop. 

Honey  sorghum  is  a  selection  from  one  of  the  earlier  introductions 
and  has  been  regarded  with  special  favor  for  syrup  purposes.  It 
produces  slender  leafy  stalks,  varying  in  height  from  eight  to  twelve 


274  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

feet.  The  heads  or  panicles  of  this  variety  resemble  somewhat  the 
Red  Amber,  though  they  are  usually  smaller,  are  less  spreading,  and 
have  yellowish  brown  glumes.  It  is  medium  late  maturing  and  has 
decidedly  tender  stalks,  which  is  particularly  important  from  a  forage 
standpoint. 

The  orange  sorghum  like  the  Honey  is  medium  late  maturing,  but 
has  rather  stout  stalks  with  long  internodes  and  broad,  though  less 
abundant  leaves.  The  plant  varies  in  height  from  eight  to  twelve 
feet,  but  its  stalks  are  much  less  tender  than  those  of  the  former 
variety.  The  seed  heads  of  this  variety  are  heavy  and  quite  compact, 
resembling  somewhat  a  head  of  kafir.  The  glumes  or  chaff  are  red 
and  black  at  maturity,  while  the  seeds  are  reddish  yellow  in  color  and 
protruding. 

Sumac,  commonly  known  as  Red-top  sorghum,  is  a  late-maturing 
variety,  with  rather  stout  stalks  and  an  abundance  of  leaves.  Its 
seed  heads  are  erect,  cylindrical  and  compact.  The  seeds  are  small 
and  reddish  brown  in  color,  and  protrude  beyond  the  glumes.  The 
glumes  also  are  very  small,  varying  from  deep  red  to  black  in  color. 
The  red  color  of  the  head  which  has  given  rise  to  the  name  ' '  Red-top ' ' 
is  due  to  the  red  color  of  the  seed.  The  plant  varies  in  height  from 
eight  to  twelve  feet  and  is  an  excellent  variety  when  the  growing 
season  is  long  enough  to  permit  its  maturity. 

Goose-neck  is  one  of  the  older  varieties  in  this  country,  and  is 
particularly  characterized  by  its  pendent  or  goose-neck  heads.  Dur- 
ing recent  years,  seed  of  this  variety  has  been  put  on  the  market  under 
the  name  of  "Texas  Seeded  Ribbon  Cane."  It  is  the  largest  of  all 
varieties,  varying  in  height  from  ten  to  fourteen  feet,  and  is  extremely 
late  maturing.  The  heads  of  the  Goose-neck  sorghums  are  rather 
thick  and  brushy,  with  shiny  black  glumes  which  completely  enclose 
the  seed.  In  the  section  where  the  growing  season  is  long,  good  results 
are  obtained  with  this  variety. 

Aside  from  the  varieties  here  discussed,  a  few  others,  such  as 
Planter's  Friend  and  Collier's,  have  been  grown  to  a  limited  extent 
in  various  sections  of  the  country.  From  an  agricultural  standpoint, 
however,  they  are  relatively  unimportant,  and  as  yet  sufficient  infor- 
mation is  not  available  concerning  their  adaption  to  California 
conditions  to  warrant  their  discussion  here. 

In  order  to  secure  more  information  as  to  the  relative  value  of 
some  of  the  more  common  varieties,  for  forage  and  silage  purposes, 
tests  were  begun  at  the  University  Farm  at  Davis  in  1914.  The  soil 
upon  which  this  test  was  conducted  is  technically  classed  as  Davis 


SWEET  SORGHUMS  FOR  FORAGE 


275 


silt  loam.  The  crop  was  grown  without  irrigation  in  all  cases  and 
on  land  which  had  produced  a  crop  of  corn  or  grain  the  previous 
season.  For  the  purpose  of  this  test,  the  crop  was  drilled  in  rows 
3y2  feet  apart,  using  about  Sy2  pounds  of  seed  per  acre.  Each  variety 
was  cut  as  soon  as  the  seed  was  ripe,  and  before  the  leaves  started  to 
wither,  or  at  the  stage  at  which  it  would  ordinarily  be  harvested  for 
silage.  The  yields  obtained  during  the  seasons  1914  to  1916  are  given 
in  table  I. 


Fig.  2. — Orange  sorghum  under  irrigation  at  the  University  Farm.  Under 
good  conditions  excellent  results  may  be  obtained  with  this  variety.  It  is  coarser 
stemmed  and  less  leafy  than  the  Honey. 


TABLE  I 

Variety  Trials  with   Sweet  Sorghum,  Davis 

(Yield  per  acre,  tons) 

Variety                                  1914                        1915  1916 

Early  Amber 8.13                   18.22  10.88 

Bed  Amber   12.61                   25.84  17.75 

Honey  26.09                   30.14  26.06 

Orange    15.53                    26.70  12.08 

Sumac  19.40                   17.26  13.87 


Average 
12.41 
18.73 
27.43 
18.11 
16.84 


276  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION 

In  these  trials  the  Honey  sorghum  has  given  strikingly  better 
results  than  any  of  the  other  varieties.  It  should  also  be  noted  that 
the  variation  in  yield  from  season  to  season  is  less  with  this  variety 
than  with  any  of  the  others.  Of  the  first  three  varieties  in  the  test, 
the  yield  is  in  proportion  to  the  length  of  the  growing  season.  The 
Early  Amber,  which  gave  the  lowest  yield,  is  an  early-maturing 
variety,  reaching  maturity  at  Davis  in  118  to  130  days.  Red  Amber 
matures  about  two  weeks  later  and  Honey  about  three  to  four  weeks 
later.  The  Orange  sorghum,  on  the  other  hand,  is  slightly  later 
maturing  than  the  Honey,  yet  gave  a  considerably  lower  yield.  The 
variation  in  yield  for  the  different  seasons  is  also  much  greater  in  the 
case  of  the  Orange  than  with  the  other  varieties.  The  relatively  lower 
yield  of  the  Sumac,  which  is  a  very  late-maturing  variety,  is  doubtless 
due  to  the  fact  that  in  none  of  the  three  seasons  did  it  reach  maturity 
before  the  fall  frosts  occurred.  Goose-neck  sorghum,  previously  dis- 
cussed, was  grown  in  1915,  but  the  crop  was  destroyed  by  frost  before 
it  had  started  to  head.  The  use  of  this  variety  as  well  as  that  of  the 
Sumac,  will  doubtless  have  to  be  confined  to  the  San  Joaquin  and 
Imperial  valleys,  where  the  growing  season  is  of  sufficient  length  to 
permit  of  their  maturing. 

In  1917  field  tests  with  three  varieties  for  silage  purposes  under 
irrigation  were  made  at  the  University  Farm  at  Davis,  and  the  re- 
sults as  reported  by  Professor  Thomas  Tavernetti  are  as  follows : 

Tons  per  acre 

Bed  Amber  22.6 

Honey    31.4 

Orange  25.6 

It  will  be  noted  that  while  the  actual  yields  were  higher  as  would 
be  expected,  the  relative  yields  are  practically  the  same  as  when  grown 
without  irrigation.  In  this  case,  however,  the  Honey  and  Orange 
varieties  were  allowed  to  stand  in  the  field  for  a  couple  of  weeks  after 
maturity  and  were  subject  to  severe  north  wind,  which  whipped  off 
a  large  proportion  of  the  leaves,  thus  lowering  the  actual  yield 
materially. 

A  variety  test  was  also  conducted  at  the  Kearney  Park  Station 
in  1917,  including  practically  all  of  the  varieties  previously  cited. 
This  test  was  conducted  on  sub-irrigated  land  and  the  results  as 
reported  by  Mr.  J.  A.  Denny,  in  charge  of  the  Kearney  Park  Station, 
are  given  in  table  II. 


SWEET  SORGHUMS  FOR  FORAGE  277 

TABLE  II 

Variety  Trials  with  Sweet  Sorghum,  Kearney  Park,  1917 

(Yield  per  acre,  tons) 

Variety  Fir?t  Second  T  .   , 

varieiy  cutting  cutting  Iolal 

Early  Amber   12.98  6.57  19.55 

Red  Amber 31.35  13.83  45.18 

Honey 37.52  13.44  50.96 

Orange 27.12  27.12 

Sumac 48.31  - 48.31 

The  fact  that  three  of  the  varieties  made  a  considerable  second 
growth  is  of  interest.  The  first  crop  of  Early  Amber,  Red  Amber,  and 
Honey  matured  the  latter  part  of  August  and  the  first  week  in  Sep- 
tember. The  second  cutting  was  made  on  November  20;  in  no  case, 
however,  had  the  second  crop  reached  maturity,  though  the  plants 
were  well  headed  out.  Since  frost  may  occur  in  that  section  at  an 
earlier  date,  the  second  growth  cannot  be  relied  upon.  The  Orange 
and  Sumac  varieties  made  a  little  second  growth,  but  not  enough  to 
be  of  any  value. 

Comparing  the  results  on  the  basis  of  the  first  crop  alone,  it  will 
be  noted  that  the  Sumac  gave  much  the  highest  yield,  with  Honey 
second.  The  Red  Amber,  in  spite  of  the  fact  that  it  matured  some- 
what earlier  than  the  Orange,  gave  a  higher  yield.  On  the  whole, 
with  the  exception  of  the  Sumac,  the  results  are  in  the  same  relative 
order  as  at  Davis. 

Goose-neck  sorghum  was  not  included  in  this  test,  but  judging 
from  results  obtained  throughout  the  valley  it  would  have  stood 
high  in  the  test  in  point  of  yield. 

In  this  connection  attention  should  be  called  to  the  fact  that  the 
choice  of  a  variety  to  be  grown  can  not  be  made  on  the  basis  of  gross 
yield  alone.  Especially  is  this  true  when  it  is  to  be  used  for  silage 
and  grown  as  a  second  crop  following  grain,  grain  hay  or  some  other 
spring  crop.  In  such  cases  earliness  of  maturity  must  also  be  con- 
sidered since  sorghum,  to  make  good  silage,  must  be  fully  matured 
when  harvested.  As  a  second  crop,  therefore,  Early  Amber  and  Red 
Amber  will  doubtless  find  the  widest  use,  while  in  sections  with  rela- 
tively long  growing  seasons  Honey  sorghum  could  be  used.  The 
number  of  days  of  growth  required  for  maturity  by  each  variety  is 
of  interest  and  is  given  in  table  III.  The  data  from  the  Davis  station 
are  averages  of  three  years,  while  the  data  from  the  Kearney  Park 
station  are  for  the  1917  crop  only. 


278  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

TABLE  III 

Period  of  Growth  of  Sweet  Sorghum 

(Number  of  days'  growth) 

Variety  Davis  Kearney  Park 

Early  Amber  124                         124 

Eed   Amber   139                         131 

Honey  153                         138 

Orange    160                          149 

Sumac  180*                       155 

*  Killed  by  frost,  not  mature. 

Attention  is  called  to  the  fact  that  in  nearly  all  cases  the  period 
of  growth  was  shorter  at  Kearney  Park  than  at  Davis.  This  difference 
is  due  primarily  to  a  difference  in  the  average  daily  temperature 
during  the  growing  season.  At  Davis  the  nights  are  rather  cool, 
resulting  in  a  somewhat  lower  average  temperature  than  that  of 
Kearney  Park.  It  should  also  be  noted  that  the  differences  for  the 
late-maturing  varieties  are  much  greater  than  those  for  the  early- 
maturing  varieties. 

These  data  are  especially  significant  in  choosing  a  variety  to  grow 
as  a  second  crop.  In  the  valley  it  is  usually  safe  to  assume  that 
growth  will  continue  until  about  the  1st  to  the  10th  of  November. 
With  the  crop  planted  by  the  15th  to  the  20th  of  June,  it  can  readily 
be  seen  that  in  the  northern  section  with  its  relatively  cooler  nights, 
only  the  earlier  maturing  varieties  could  be  used,  while  in  the  warmer 
section  the  Honey,  and  in  some  cases  the  Orange  variety  could  be 
relied  upon  to  reach  maturity  with  a  fair  degree  of  certainty. 

The  data  also  show  that  only  in  the  most  favorable  sections  can 
the  late-maturing  varieties,  such  as  Sumac  and  Goose-neck,  be  relied 
upon  to  reach  maturity,  even  where  planted  at  the  earliest  possible 
date. 

CULTURE 

The  cultural  treatment  necessary  for  the  successful  production  of 
the  sweet  sorghums  is  essentially  the  same  as  those  for  the  production 
of  the  grain  sorghums2  and  sudan  grass3  which  are  discussed  in 
previous  publications.  Where  they  are  to  be  grown  as  a  dry-farm 
crop,  special  emphasis  must  be  placed  on  the  storage  and  conservation 
of  moisture,  the  preparation  of  the  seed  bed,  and  the  care  of  the  crop 
during  the  growing  season.     This  is  especially  important  since  the- 

2  Univ.  Calif.  Agr.  Exp.  Sta.  Bui.  278. 

3  Univ.  Calif.  Agr.  Exp.  Sta.  Bui.  277. 


SWEET  SORGHUMS  FOR  FORAGE  279 

crop  is  grown  during  the  dry  season  of  the  year,  and  though  it  is 
quite  tolerant  of  drouth,  the  results  obtained  will  usually  be  in  pro 
portion  to  the  supply  of  moisture  and  the  condition  of  the  soil. 

Preparation  of  the  Seed  Bed. — For  the  best  results  the  land  should 
be  plowed  rather  deeply  in  the  fall  or  early  winter  winter  before  the 
heavy  rains  begin,  and  allowed  to  remain  rough  until  spring.  In  this 
condition  the  soil  will  absorb  a  large  proportion  of  the  rainfall  and 
will  also  be  materially  benefitted  by  the  weathering  action.  As  soon 
as  most  of  the  rains  are  over,  the  surface  of  the  soil  should  be  worked 
down  to  a  good  mulch  with  a  disc  and  harrow  and  maintained  in  that 
condition  until  planting  time.  When  spring  plowing  is  necessary  it 
should  be  somewhat  more  shallow  than  fall  plowing,  otherwise  too 
much  work  will  be  required  to  prepare  the  land  properly.  It  is,  in 
fact,  nearly  always  more  difficult  to  prepare  a  good  seed  bed  on  spring 
than  on  fall-plowed  land.  Where  sorghum  is  to  be  grown  as  a  second 
crop,  following  grain  or  grain  hay,  the  usual  procedure  is  to  irrigate 
the  land,  plow  rather  shallow,  and  then  work  down  immediately  to  a 
seed-bed  condition. 

The  seed  bed  should  be  smooth  and  even,  with  a  mulch  of  two  to 
three  inches  on  the  surface.  The  soil  below  the  mulch  should  be  firm 
and  moist.  If  the  soil  is  too  loose  for  a  good  seed  bed,  rolling  may  be 
necessary  before  planting  the  crop  to  pack  the  soil  and  bring  the 
moisture  nearer  to  the  surface.  The  best  implement  for  this  purpose 
is  a  corrugated  or  Dunham  roller. 

Time  of  Seeding. — As  a  rule,  sorghums  should  be  planted  some- 
what later  than  Indian  corn.  Planting  should  riot  be  done  until  the 
soil  has  warmed  up  sufficiently  for  prompt  germination.  If  the  soil 
is  too  cold,  the  seed  will  germinate  slowly,  and  the  subsequent  growth 
is  apt  to  be  stunted.  In  the  Sacramento  and  coast  valleys,  the  best 
time  to  plant  is  about  the  middle  of  April.  In  the  San  Joaquin  and 
Imperial  valleys,  planting  may  be  done  about  April  1.  On  the  other 
hand,  if  planting  is  delayed  until  the  first  to  the  middle  of  May,  the 
soil  is  apt  to  become  too  dry  to  germinate  the  seed,  unless  irrigation 
can  be  provided.  On  irrigated  land,  planting  may  be  delayed  as  late 
as  the  middle  to  the  latter  part  of  June.  This  fact  is  made  use  of  by 
employing  the  sorghum  as  a  second  crop.  In  such  cases,  however,  an 
early-maturing  variety  should  be  used. 

Method  and  Bate  of  Seeding. — The  method  of  seeding  sorghums 
will  be  determined  largely  by  the  purpose  for  which  they  are  grown. 
When  the  crop  is  to  be  used  for  fodder  or  silage,  it  is  usually  planted 
in  rows  3  to  3%  feet  apart,  using  about  2%  to  4  pounds  of  seed  per 


280  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

acre.  The  exact  rate  of  seeding  must  be  governed  by  the  character 
of  the  soil  and  the  supply  of  moisture.  On  strong  soil  well  supplied 
with  moisture,  the  heavier  rate  of  seeding  may  be  used,  while  on  soils 
of  doubtful  fertility  and  only  moderately  well  supplied  with  moisture, 
lighter  seeding  should  be  practiced. 

The  implement  commonly  used  for  planting  the  crop  is  the  corn 
planter,  fitted  with  sorghum-seed  plates.  The  grain  drill  is  also  some- 
times used  by  stopping  up  enough  of  the  holes  to  give  the  proper 
spacing.  This  implement,  however,  often  plants  too  shallow  and  uses 
more  seed  than  necessary  for  the  best  results. 

The  depth  to  which  the  seed  should  be  planted  will  vary  with 
the  character  of  the  soil  and  the  condition  of  the  seed  bed.  It  is 
important,  however,  to  plant  the  seed  deeply  enough  so  that  it  is 
placed  in  contact  with  moist  soil  where  it  may  quickly  absorb  the 
moisture  necessary  for  germination;  ordinarily  two  to  three  inches 
in  depth  is  sufficient. 

When  sorghum  is  to  be  grown  for  hay  or  pasture,  it  is  usually 
seeded  broadcast  or  in  close  drills  like  grain.  For  this  purpose  the 
grain  drill  is  the  most  efficient  implement  to  use  as  it  places  all  the 
seeds  in  the  soil  at  a  uniform  depth.  Broadcasting  is  not  as  good, 
since  much  of  the  seed  will  not  be  covered  deeply  enough  to  get  into 
moist  soil  and  hence  will  not  germinate.  The  usual  rate  of  seeding 
sorghum  in  close  drills  is  from  30  to  40  pounds  per  acre.  Wheii 
seeded  broadcast,  more  seed  must  be  used  per  acre  in  order  to  get  a 
good  stand. 

Care  of  the  Crop. — The  cultivation  which  the  crop  will  require 
after  planting  will  depend  to  a  large  extent  on  the  condition  of  the 
field  and  the  season.  The  sorghums  grow  rather  slowly  at  first  and 
if  the  field  becomes  weedy,  while  the  plants  are  yet  quite  small,  the 
weeds  may  be  destroyed  with  a  harrow  without  severe  injury  to  the 
crop.  On  the  other  hand,  if  the  surface  of  the  soil  becomes  crusted 
while  the  plants  are  small  or  before  the  seedlings  appear,  this  crust 
must  be  broken,  otherwise  injury  to  the  young  plants  is  apt  to  result. 
If  the  crust  is  not  too  thick  it  may  be  broken  with  a  light  harrow,  but 
a  better  implement  to  use  is  a  corrugated  or  Dunham  roller,  which 
pulverizes  the  surface  without  tearing  out  the  plants.  When  the 
crop  has  been  planted  in  rows,  3  to  3%  feet  apart,  it  should  be 
cultivated  as  soon  as  the  plants  are  large  enough  so  that  the  row  can 
be  seen  plainly.  Two  to  three  similar  cultivations  should  be  given 
at  intervals  of  two  to  three  weeks,  or  until  the  plants  attain  a  height 
of  about  three  feet,  after  which  no  further  cultivation  will  be  neces- 


SWEET  SORGHUMS  FOR  FORAGE  281 

s&ry.  When  the  crop  is  irrigated  it  is  well  to  cultivate  after  each 
irrigation  in  order  to  reestablish  the  mulch  and  prevent  evaporation. 

The  first  cultivation  of  the  season  should  be  rather  deep  in  order 
to  form  a  good  deep  mulch  and  force  deep  rooting.  Later  cultivation, 
however,  should  be  more  shallow. 

Where  sorghums  are  grown  in  close  drills  for  hay  or  for  pasture, 
no  cultivation  is  possible  other  than  the  initial  harrowing  while  the 
plants  are  small. 

Irrigation. — While  the  sorghums  are  preeminently  dry-land  crops, 
the  application  of  water,  whenever  possible,  will  in  nearly  all  cases  be 
amply  justified  by  the  increased  yields.  The  use  of  the  sorghums  as 
a  second  crop  following  grain  or  grain  hay,  will  be  possible  only  under 
irrigation.  In  such  cases  the  land  must  be  irrigated  before  planting 
in  order  to  insure  sufficient  moisture  to  germinate  the  seed. 

The  time  of  irrigation  and  the  number  of  irrigations  will  depend 
wholly  upon  local  conditions.  The  best  time  to  irrigate  the  growing 
crop  is  when  the  plants  start  to  head.  From  this  time  on  the  plants 
are  making  their  most  rapid  growth  and  hence  are  drawing  heavily 
upon  the  moisture  supply.  When  the  land  has  been  well  watered 
before  planting,  the  crop  can  usually  be  matured  without  further 
irrigation.  In  many  instances,  however,  one  additional  irrigation  may 
prove  beneficial.  Late  irrigation  particularly  should  be  avoided  as  it 
greatly  stimulates  the  growth  of  suckers,  causing  the  product  to 
mature  unevenly.  There  is  also  a  tendency  to  increase  lodging  and  to 
stimulate  a  second  growth  prematurely  if  water  is  applied  too  late. 

Sorghums  may  be  irrigated  either  through  furrows  or  by  flooding. 
Where  the  condition  of  the  field  will  permit,  the  latter  method  is  to 
be  preferred,  because  of  the  smaller  amount  of  labor  involved. 


HARVESTING 

Sorghums  which  are  being  grown  for  silage  should  not  be  cut 
until  the  seed  is  in  the  hard  dough  stage.  If  cut  earlier  the  silage 
is  apt  to  be  sour  and  of  poor  quality.  To  avoid  this  possibility  it  is 
even  better  to  allow  the  seed  to  become  fully  mature  before  cutting. 
It  is,  of  course,  true  that  as  the  plants  reach  maturity  the  fiber 
increases  rapidly,  but  this  is  less  objectionable  in  silage  than  in  other 
forms  of  forage.  The  usual  method  of  harvesting  is  with  a  corn 
binder. 

For  fodder  purposes  sorghum  may  be  cut  at  any  time  after  the 
heads  are  formed.     Probably  the  best  stage  of  growth  is  just  as  the 


282  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

seed  is  forming  or  while  it  is  in  the  milk.  In  this  stage  the  crop  has 
practically  attained  its  maximum  growth,  while  the  plants  are  less 
fibrous  and  hence  of  higher  feeding  value  than  if  allowed  to  become 
more  nearly  mature. 

The  fodder  crop,  like  the  silage  crop,  is  usually  cut  with  a  corn 
binder.  Where  the  climate  is  dry  the  bundles  may  at  once  be  set  in 
shocks  to  cure,  after  which  they  may  either  be  fed  directly  from  the 
field  or  put  into  a  stack.  In  the  more  humid  sections  more  care  is 
necessary  to  prevent  the  fodder  from  molding.  Ordinarily  the  bun- 
dles should  be  allowed  to  dry  for  a  few  days  on  the  ground  after  which 
they  are  set  up  into  small  shocks  to  complete  the  curing  process. 

When  seeded  broadcast  or  in  close  drills  for  hay,  the  best  time  to 
harvest  compatible  both  with  maximum  yields  and  feed  value,  is  when 
the  plants  start  to  head.  By  harvesting  at  this  stage  of  growth,  two 
and  sometimes  three  cuttings  per  season  may  be  obtained.  Further- 
more, if  cut  at  this  stage  the  stems  are  soft  and  succulent  and  if 
properly  cured  will  be  readily  eaten  by  livestock. 

The  hay  crop  is  commonly  cut  with  a  mower  and  allowed  to  cure 
in  the  swath  for  a  day  or  two,  after  which  it  is  raked  into  windrows 
and  then  put  into  cocks  to  complete  the  curing  process.  This  is  the 
most  rapid  method  of  getting  rid  of  the  moisture,  but  often  results 
in  a  harsh  hay.  The  method  preferred  by  many  is  to  allow  the  hay 
simply  to  wilt  in  the  swath  and  then  to  put  it  into  small  size  cocks  to 
cure.  By  this  process  the  hay  cures  more  slowly,  but  retains  its  color 
and  is  believed  to  result  in  a  more  palatable  feed. 

In  a  few  instances,  the  grain  binder  has  been  used  for  harvesting 
the  hay  crop,  the  bundles  being  set  up  into  small  shocks  to  cure.  With 
a  heavy  crop,  however,  some  difficulty  will  be  experienced  in  getting 
the  binder  to  handle  it.  The  chief  advantage  for  this  method  is  that 
it  is  easier  to  handle  the  fodder  in  bundles  than  when  it  is  loose. 

Danger  from  Poisoning. — When  sorghums  are  pastured  or  fed 
green  apprehension  is  sometimes  felt  regarding  the  danger  to  stock 
from  poisoning.  Under  certain  conditions  when  the  plants  are 
stunted  in  their  growth,  prussic  (hydrocyanic)  acid,  which  is  quickty 
fatal  to  stock,  develops  in  the  leaves.  With  the  plants  in  a  normal, 
thrifty  state  of  growth,  this  danger  is  practically  nil.  In  fact,  the 
proportion  of  losses  from  sorghum  poisoning  as  compared  with  losses 
from  other  preventable  causes  is  very  small.  When  the  plants  are 
cured  the  poison  disappears  from  the  leaves,  so  that  there  is  no  danger 
from  feeding  the  cured  forage,  nor  have  any  losses  been  reported  from 
feeding  sorghum  silage. 


SWEET  SORGHUMS  FOR  FORAGE  283 


SORGHUM    IN   THE    ROTATION 

Sorghums  may  be  employed  in  the  rotation  like  Indian  corn  or 
any  other  spring  crop.  While  they  are  reported  to  be  hard  on  the 
land,  there  is  no  evidence  to  show  that  they  take  from  the  soil  any 
more  plant  food  in  proportion  to  their  growth  than  other  crops. 
Because  of  the  fact  that  the  sorghum  roots  are  bunched  near  the  sur- 
face of  the  ground,  they  do  leave  the  soil  in  poor  physical  condition, 
which  probably  accounts  for  the  observed  injurious  effect  on  the  suc- 
ceeding crop.  If,  however,  the  land  is  plowed  as  soon  as  the  crop  is 
removed,  and  allowed  to  aerate  for  a  month  or  more  before  seeding, 
any  injurious  effect  of  the  sorghum  on  the  soil  will  practically  dis- 
appear. 

Sorghum,  however,  should  not  be  grown  on  the  same  land  many 
years  in  succession.  Continuous  cropping  to  sorghum  will  soon  result 
in  a  poor  yield.  This  is  indicated  to  some  extent  in  a  test  at  Davis, 
started  in  1914,  the  data  on  which  are  given  in  table  IV. 


TABLE  IV 

Effect  of  Eotation  on  Sorghum 

Year                                   Sorghum 
continuous 

Sorghum 
after  corn 

1914  .... 

7.00 

8.13 

1915  .... 

12.63 

18.22 

1916  .... 

7.73 

17.75 

1917  .... 

8.22 

On  the  continuously  cropped  series,  Early  Amber  was  used  in  1914 
and  1915,  and  Red  Amber  in  1916  and  1917.  During  the  last  two 
years,  however,  the  plants  in  the  series  were  weak  and  sickly  looking, 
even  early  in  the  season,  while  the  growth  on  the  whole  was  inferior 
to  that  of  the  crop  following  corn. 

Some  growers  have  had  difficulty  of  disposing  of  the  stubble  and 
roots  after  the  crop  has  been  harvested.  If,  however,  a  fourteen  or 
sixteen  inch  mouldboard  plow  or  a  large  disc  plow  is  used,  and  the 
field  plowed  soon  after  the  crop  is  harvested,  the  stubble  can  be 
turned  under  quite  readily.  The  large  crowns  will  ordinarily  be 
sufficiently  disintegrated  by  the  winter  rains  to  cause  but  little 
trouble. 


STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


REPORTS 

1897.     Resistant  Vines,  their  Selection,  Adaptation,   and  Grafting.     Appendix  to  Viticultural 
Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment  Station  for   1898-1901. 

1903.  Report  of  the  Agricultural  Experiment   Station  for   1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-04. 

1914.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

1915.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

1916.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 

1917.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment  Station. 


No. 

230. 
241. 
242. 
246. 
248. 

250. 
251. 


252. 
253. 

255. 
257. 
261. 

262. 

263. 
264. 
265. 
266. 

267. 
268. 
270. 


No. 
113. 
114. 
115. 
121. 

124. 
126. 
127. 
128. 
129. 
131. 
133. 
135. 
136. 
137. 
138. 
139. 


140. 


142. 

143. 

144. 
147. 
148. 
150. 
151. 
152. 

153. 

154. 

^r,^,. 
ir,<\. 

15  7. 
J  58. 


BULLETINS 

No. 

271. 
272. 
273. 


Enological  Investigations. 

Vine  Pruning  in  California,  Part  I. 

Humus  in  California  Soils. 

Vine  Pruning  in  California,  Part  II. 

The  Economic  Value  of  Pacific   Coast  274. 

Kelps. 
The  Loquat.  275. 

Utilization  of  the  Nitrogen  and  Organic 

Matter    in    Septic    and    Imhoff   Tank  276. 

Sludges.  277. 

Deterioration  of  Lumber.  278. 

Irrigation   and   Soil   Conditions   in  the  279. 

Sierra  Nevada  Foothills,  California.  280. 

The  Citricola  Scale. 

New  Dosage  Tables.  282. 

Melaxuma    of    the    Walnut,     "Juglans 

regia."  283. 

Citrus   Diseases   of   Florida   and   Cuba  284. 

Compared  with  Those  of  California.  285. 

Size  Grades  for  Ripe  Olives.  286. 

The  Calibration  of  the  Leakage  Meter.  288. 

Cottony   Rot  of   Lemons   in   California. 
A  Spotting  of  Citrus  Fruits  Due  to  the  290. 

Action  of  Oil  Liberated  from  the  Rind. 
Experiments  with  Stocks  for  Citrus.  291. 

Growing  and  Grafting  Olive  Seedlings. 
A  Comparison  of  Annual  Cropping,  Bi- 
ennial Cropping,  and  Green  Manures 

on  the  Yield  of  Wheat. 

CIRCULARS 

No. 

Correspondence  Courses  in  Agriculture.  160. 

Increasing  the  Duty  of  Water.  161. 

Grafting  Vinifera  Vineyards.  162. 

Some    Things   the    Prospective    Settler 

Should   Know.  164. 

Alfalfa   Silage  for  Fattening  Steers.  165. 

Spraying  for  the  Grape  Leaf  Hopper. 

House  Fumigation.  166. 

Insecticide  Formulas.  167. 

The  Control  of  Citrus  Insects.  168. 

Spraying  for  Control  of  Walnut  Aphis. 

County  Farm  Adviser.  169. 

Official  Tests  of  Dairy  Cows.  170. 

Melilotus  Indica. 

Wood  Decay  in  Orchard  Trees.  172. 

The  Silo  in  California  Agriculture.  174. 

The    Generation    of   Hydrocyanic   Acid  175. 
Gas  in  Fumigation  by  Portable  Ma- 
chines. 176. 

The  Practical  Application  of  Improved 

Methods  of  Fermentation  in  Califor-  177. 

nia  Wineries  during  1913  and  1914.  181. 

Practical  and  Inexpensive  Poultry  Ap- 
pliances. 182. 

Control    of    Grasshoppers    in    Imperial 

Valley.  183. 

Oidium  or  Powderv  Mildew  of  the  Vine.  184. 

Tomato  Growing  in  California.  185. 

"Lungworms." 

Round  Worms  in  Poultry.  186. 

Feeding  and  Management  of  Hogs.  187. 

Some  Observations  on  the  Bulk  Hand-  188. 

ling  of  Grain   in   California.  190. 

Announcement  of  the  California  State  191. 

Dairv  Cow  Competition,    1916-18.  192. 

Irrigation    Practice   in    Growing   Small  193. 

Fruits  in  California.  196. 

Bovine  Tuberculosis.  197. 

How  to  Operate  an  Incubator. 

Control  of  the  Pear  Scab.  198. 

Home  and  Farm  Canning. 


Feeding  Dairy  Calves  in  California. 

Commercial  Fertilizers. 

Preliminary  Report  on  Kearney  Vine- 
yard Experimental  Drain. 

The  Common  Honey  Bee  as  an  Agent 
in  Prune  Pollination. 

The  Cultivation  of  Belladonna  in  Cali- 
fornia. 

The  Pomegranate. 

Sudan  Grass. 

Grain   Sorghums. 

Irrigation  of  Rice  in  California. 

Irrigation  of  Alfalfa  in  the  Sacramento 
Valley. 

Trials  with  California  Silage  Crops  for 
Dairy  Cows. 

The  Olive  Insects  of  California. 

Irrigation  of  Alfalfa  in  Imperial  Valley. 

The  Milch  Goat  in  California. 

Commercial  Fertilizers. 

Potash  from  Tule  and  the  Fertilizer 
Value  of  Certain  Marsh  Plants. 

The  June  Drop  of  Washington  Navel 
Oranges. 

The  Common  Honev  Bee  as  an  Agent 
in  Prune  Pollination.     (2nd  report.) 


Lettuce  Growing  in  California. 

Potatoes  in  California. 

White    Diarrhoea    and    Coccidiosis    of 

Chicks. 
Small  Fruit  Culture  in  California. 
Fundamentals    of    Sugar    Beets    under 

California    Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morn- 

ing-Glory  within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing     California     Soils     for     the 

1918  Crop. 
Wheat  Culture. 
Farm  Drainage  Methods. 
Progress  Report  on  the  Marketing  and 

Distribution  of  Milk. 
Hog     Cholera     Prevention     and     the 

Serum  Treatment. 
Grain  Sorghums. 
Control     of     the     California     Ground 

Squirrel. 
Extending  the  Area  of  Lvrigated  Wheat 

in   California  for   1918. 
Infectious  Abortion  in  Cows. 
A  Flock  of  Sheep  on  the  Farm. 
Beekeeping  for  the  Fruit-Grower  and 

Small  Rancher,  or  Amateur. 
Poultry  on  the  Farm. 
Utilizing  the  Sorghums. 
Lambing  Sheds. 

Agriculture  Clubs  in  California. 
Pruning  the  Seedless  Grapes. 
Cotton  in  the  San  Joaquin  Valley. 
A  Study  of  Farm  Labor  in  California. 
Dairy  Calves  for  Veal. 
Suggestions    for    Increasing    Egg    Pro- 
duction in  a  Time  of  High-Feed  Prices. 
Syrup  from  Sweet  Sorghum. 


